There are many engineering challenges involved in traveling to the Moon and inparticular there is strongneed in advancedrobotics. Robot will beneeded in space for in-space assembly and maintenance surface in-space exploration and human assistance.

Robots mustbe able to function in unknown unstructured and dynamic environments.Mars is a cold, dry planet with extreme temperatures and a thin atmosphere.The terrain isrough and often untraversable. Other materials, such as ore grade metals, petroleum

minerals, if they exist, need to be discovered.

We are in need for a multipurpose robotic module that would explore Mars. Weare alsoin need of multiple robotic modules which would coordinate among each other andexplore Mars.

All these robots have been fixed with localsensors, so they canonly identify objectscloser to them. These robotshave to communicate between each other during the task

This paper develops a control logic thatwill enable multipurpose robotic systems tonavigate and coordinate with other roboticmodules. Weare currently working on variouscommunication and navigational set up. Wehavealso comeup with an idea of LightCommunication in case ofmultiple roboticsystems. The idea behind thispaper isexperimented with three robotic modules. There might someabnormal conditions such asbreakdown of down of the autonomous roboticmodules. In that case, wehave built amanually controlled robotic rescuer modulewhich helps the other robotic systems torecover from the abnormalities.

In other words this paper is based on five categories

!

Lead robotic System(Multipurpose)!

RF Robotic Communication module!

Light chaser robot (Formation control)!

Rescuer Robot!

Mission Completion Robot

Lead Robot(Multipurpose)(TestingPiece on Earth)

This paper proposes a new idea that will enable multipurpose mobile robotic systems toperformmultiple tasks in a domestic environment, such as i)monitoring alocalenvironment ii) detecting unusual situations such as trespasses, bombs, fire, gas leakageusing a multiple sensor system. iii) Object Recognition and Navigation ObjectRecognitionand Navigation for mobile robots has been one ofthe major problems in theresearch of Artificial Intelligence. Without this ability, thepossibilities for robots to carryout useful tasks (as mentioned above) remainlimited. The Robot has to have a betterefficiency inunderstanding the environment. Wehave developed a simple multipurposerobot with a highly reliable GaAs – IRSensor forsensing and analgorithm for navigationalong with reverse gear facility.Wehave tested our multipurpose robot in performing theabove mentioned tasks with satisfactory results and are currently researching for

improving the reliability and scopeofthe robot inreallifesituations. The leadrobot ismultipurpose in nature. The LeadRobot (RF Module) will beassisted by the followerrobot. The RF Module a PIC16c77 with a RTD-AM transceiver module fromAbacom.

There were a lot of disadvantages in the RF module when were tying to establish acommunication betweenthe Lead Robotic Systemand Follower Robotic Systemsuch asreceiver end failures and bursty communication problems. So to overcome thedisadvantages of RF Communication, Webuilta Light Chaser Robotic systemwhichwould take part in the formation approach.Wecould efficiently make a formation amongthe robotic systems with light. The robot will turn towards the brightest light and moveforward chasing or following it. It has twomotors (left & right) in order to make theturns; on top two light sensors (photodiodes) separated by a PCboard in order to simulate"a nose". This nose isparticularlyimportant because it will providea shadow thuspreventing both sensors frombeing illuminated when a side light is present (the motor onthe non-illuminated sensor side will turnon thus aiming the robot towards the light).When the light is right in front of the sensors, there will be no shadow and both sensorswill be equally illuminated, i.e.: both motors will be running and the robot will moveforward.

The main robot board was anold kit; it had

two IR pairs ofsensors (emitter-receptor)to

read a rotating cardboard circle painted black and white in twocircumferences. Thissequence of black and white sectors programmedthe robot to make turns, move forward,stop, etc. This part of the circuit was removed and a new circuit was designed and put inplace. The creature has been equipped with speech and voice detection circuits.

These robotic modules have been tested with various experiments on earth. Weare trying todevelop a control logic using a tool called Petri Net Kernel, which would helpus to analyse thebehavior of Coordinated Multipurpose roboticsystems with RF andLight Communicationchannels.

Objectives of the Research:

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Reliable control logic using C Interface.

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Multi –Robot Coordination with RF Modules

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Experiments with two cheap and simple robots.

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Visualize and check the state ofeach robot

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Control Logic with short range sensor information.

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2D – Stimulation Using Stimulation Softwares.

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Reverse Gear Facilities.

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Metal Detection, Gas Leakage Detection

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Highly Sensitive Circuit Breaking

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Active Guidance for the Blind.

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Victim Detection during disasters.

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Object Avoidance and Path Indentification

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AC and DC Facilities

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Fire/Heat Sensing Mechanism

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Light Chasing – Coordination

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Rescuer Robot

System Architechture: Lead Robot:

Lead Robot(Multipurpose)

It has a microcontroller AT89C51 and two stepping motors. The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flashprogrammable anderasable read only memory (PEROM). The device ismanufacturedusing Atmel’s high-density nonvolatile memorytechnology and is compatible with theindustry-standard MCS-51 instruction setand pinout. The on-chip Flash allows the

programmemory to be reprogrammed in-systemor by a conventional nonvolatilememory programmer. By combining a versatile 8-bit CPU with Flash ona monolithic

chip, the Atmel AT89C51 is a powerfulmicrocomputer which provides a highly-flexible and cost-effective solution tomany embedded control applications.

The 555 monolithic timing circuit is a highly

stable controller capable of producing

accurate time delays, or oscillation.Inthe time delay mode of operation, the time is

precisely controlled by one external resistorandcapacitor. For a stable operation as an

oscillator, the free runningfrequencyand the dutycycle are both accuratelycontrolledwith two externalresistors and

one capacitor. The circuit may be triggeredand reset onfallingwaveforms, and theoutput structurecan sourceor sink upto

200mA.

GaAs-IR-Lumineszenzdiode - GaAs InfraredEmitter is used. Some of the features

The MC78XX/LM78XX/MC78XXA series ofthreeterminal positive regulatorsareavailable in the TO-220/D-PAK package andwith several fixed output voltages, makingthemuseful in a wide range of applications. Each type employs internal current limiting,thermal shut down and safe operating area protection, making it essentially indestructible.If adequate heat sinking is provided, theycan deliver over 1Aoutput current. Althoughdesigned primarily as fixed voltage regulators,these devices can be used with externalcomponents to obtain adjustable voltagesand currents. The TSOP17.. – series areminiaturizedreceivers for infrared remotecontrol systems. PIN diode and preamplifierare assembled on lead frame, the epoxy package is designed as IR filter.The demodulated

output signal can directly bedecoded by a microprocessor.TSOP17.. is the standard IR

remote control receiver series, supporting all major transmission codes.

In this fire alarmcircuit, a thermistor works as the heat sensor. When temperatureincreases, its resistance decreases, and viceversa. At normal temperature, the resistanceofthe thermistor(TH1) is approximately10 kilo-ohms,which reduces to a few ohms

as the temperature increases beyond100°C.The circuit uses readily availablecomponents and can be easily constructed on any general-purpose PCB

Specificationfor the CCTV Camera:

Wireless code transaction cantransmit and Receive pictures through wall with highresolution up to 100 meteres.

Power Supply:9 – 12 VDCDistance: Wireless Transmission(100 Meteres)\

Basic Mechanical Design:

Top View:

Fig 1:

Fig 1 shows the basic working model.

Fig2: The design of the Lower Portion:

The above block shows the basic mechanical design of the multipurpose robotalong with the basic components. The CCD Camera, Guide Cane and theSquirting Components are detachable. They are to be attached during need.The differentially steered robotis similar to the differentialgearsused in automobilesinthat both the wheels can have different rates ofrotations, but unlike the differentialgearingsystem, a differentiallysteered systemwill have both the wheels powered.Differential wheeled robots areused extensively in robotics,since their motion is easyto programand can be well controlled. Thedimensions of the Robot are 31 * 21 cms.

Somemechanical considerations such as caster angles have beentaken in to accountwhile designing the robot. Provisions have been given for extension of the tasks doneby the robot. A chamber has been designed for holding the batteries. It runs on AC andDC supplies.

It has microchip pic 16c77.and two stepping motors. The robotic module has atransceiver module AM-RTDfromabacomfor serial data communication. The robotcan estimate its moved distance anddirection fromthe initial position using encoders.Note that only relative distance and direction from a particular point can be recognized

System Architechture Follower Robot: 2 (Light Chaser)

Our Light Chaser robot requires aninternal locomotor Systemdriven by two electric motors thatdraws its energy froma rechargeable battery. Itis completed by three wheels out of which twowheels are driven by the electric motor and thethird one acts as a differential wheel thathelps

the robot to turn 360degrees. It consists of twolight sensitive cells consisting of light dependentresistors that provide the electronic creature with directional light sensing behavior. The two eyesare fitted with LDRs placed at adequate distance fromeach other. If the light impinges laterally ,then one of the two LDR’s is subjected to less light thanthe other,the result is that the motors

electronics circuitry executesa change of course which lasts until the light impinges and fromthe front and both LDR’s are subjected to sameamount of light.The Rescuer Robot:

The rescuer robot consists offour DC motors operated by relays which act as a switch.The voltage regulator I used to provide 6Vto the relay. The motors are supplied 12V

froma DC Source. The robot is manuallyoperated using a remote (RF). The Roboticmodule can push upto 10Kgs and lift upto 1Kg.

Functional Analysis:

Lead Robot:

Obstacle Avoidance and Navigation:

We have used a IC 555 timer(Astable Multivibrator) for modulating the IR LEDtoproduce IR at frequency of 38KHz. When an obstacle is detected by any one of the IRSensors, the IR reflected fromthe surface of the obstacle isreceived by the IR receiver

(capacity of receiving IRup to 38 KHz). Itgives a pulse to microcontroller (AT89C51).The algorithmhas been written for the following behavior of the robot.When it detectsan obstacle in the right, the left motor stops and the right motor continues to rotate, so the

it turns towards the left. When the obstacleis detected in the left, the robot movestowards theright usingthe sameprincipal (Tangential Turning Principle). In case ofobstacle in both the sides, the move continues to move forward. In case of an obstacle onall the three sides, the robotgets back (Reverse Gear Facility) and searches in all

directions and finds a path to move.

Metal Detection and Gas Leakage Detection.

The goal ofour robot is for it to beable todetect land mines. Obviously, somesort of

sensor must be incorporated into thesystemthat is able to find landmines. Wechose toinitially use a simple metal detectoras amine detecting device.

The metal detector used on our robots utilizes a fairly simple design. The maincomponent of the metal detector is the induction coil. When a metal object comes neat tothe coil, it'sinductance is affected. This is turn altersthe oscillation frequency of thecircuitry. The alteration can bedetected, and act as a "stop" command forthe robot.Heat detectors use a setof temperature-sensitive resistors

called thermistors thatdecrease

in resistance as the temperature rises. One thermistor is sealed and protected from thesurrounding temperature while the other isexposed. A sharp increase in temperaturereduces the resistance in the exposed thermistor, which allows a large current to activatethe detector'salarm.

The CCD photosites accomplish their taskof sensing incoming light through thephotoelectric effect, which is a characterization of the action of certain materials torelease an electron whenhit with a photon oflight. The electrons emitted within the CCDare fenced within nonconductiveboundaries, so that they remain within thearea of the

photon strike. As long as lightis allowed toimpinge on a photosite, electrons willaccumulate in that pixel. When the source oflight is extinguished (e.g., the shutter is

closed),simple electronic circuitry and a microprocessor or computer are used tounloadthe CCD array, count the electrons in each pixel, and process the resulting data intoanimage on a video monitor or other output media. So victims can be identified duringdisasters and the output media ismade available to the rescuers.

Commercial Applications and Marketability ofOur Multipurpose Robot:

Due to its is multifunctional capabilities, itis highly useful to the present society.

Automatic fire detection systems, when combined with other elements of an emergencyresponse and evacuation plan, can significantly reduce property damage, personalinjuries, andloss oflife fromfire in the workplace. Their main function is to quicklyidentify a developing fire and alert building occupants and emergency response personnelbefore extensive damage occurs. Automatic fire detection systems do this by usingelectronic sensors to detect the smoke, heat, or flames froma fire and providing an earlywarning.

Being an autonomous vehicle, the above tasks are impossible without object avoidanceand navigations techniques. Wehave developed an alogorithm to increase the efficiencyin understanding the environment with sharp sensors. Wehave tested out robot inperforming the above mentioned task and theresults were satisfactory. Weare workingon mechanical considerations such as differential steering, angle of camber, etc…., weare currently working on improving itsscope for real life situations.

Formation Control:

In this paper, only inaccurate sensor information is available for coordinatingtheformation of multiple mobile robots.Local sensorinformation means that all therobots have only local sensors that cannotaccurately measure absolute distances and directions of objects. That is, all the sensorshave limitation on the range and uncertainty inthe values. It is possible to recognizetypes of the detected object by using the frequency of the light asrobot ID. Each robothas a unique fixed sensor frequency. If a robotreceives its own frequency, it recognizesthe object is static. If a robot receives a frequency of another robot, it can recognize theID of the detected robot.The surfaces of all robots are coveredwithblack tapes topreventreflection of light. Therefore,a robot cannot receive its

own frequency reflected byanother robot.

Computational Modeling of Coordinated Robotic Systems:

A main goal of computational robotics is toautomatically synthesize robot motions toachieve a given task. This course discusses geometric and algorithmic issues that arise insuch an endeavour. Examples of a few sub-problemsthat need to be addressed are: howcan a robot plan its own collision-free motions?How does it grasp a given object? Howdoes one account for uncertainty?The courseemploys a broad range of tools from

computational geometry, mechanics and controltheory. The behavior is plotted with PetriNet Models.

Behavior of Robotic Systems:

.

Conclusion:Being an autonomous vehicle, the abovetasks are impossible without objectavoidance and navigations techniques. Wehavedeveloped an algorithm to increase theefficiency in understanding the environment withsharp sensors. Wehave tested out robotin performing the above mentioned task andthe results were satisfactory and we couldsatisfy all our objectives to a greater extent. We are working on considerations such asdifferential steering, angle ofcamber, etc…., weare currently working on improving itsscope for real lifesituations. Themulti - robot coordination has proved to be quitesuccessful. We have overcomethe disadvantages of RF Communication with a new

concept of using light toestablish a communication between

multiple robotic modules in

a domestic environment. We have also verified the performance of the Rescuer Robot.

Note: Weconducted real timeexperimentsand have taken videos during our research.Most of our objectives have been satisfied. Ihave attached the photos of the Lead and theother two follower robotic systems, if needed I shall send the videos. I’mlooking forwardto present my ideas along with the working model during the event. All the threeworking models shall be available during presentation at IIT – Bombay.